Monday, December 2, 2013

Problems with Infinity


In my “God of the Naturally Insurmountable Abyss” argument, which is an expanded Kalam Cosmological Argument, I claimed that “An infinite regress of causes is impossible”, but never explained why this is.  Here’s my attempt as a finite being to explain why an infinite number of things, time, causes, etc cannot exist in reality. 

The first step is to define infinity, which is not easy to do.  Webster’s online dictionary says infinity is the quality of having no limits or end.  As this Numberphile video points out, “Infinity is not a number.  It’s an idea.  It’s a concept.”  According to the Internet Encyclopedia of Philosophy, there are three types of infinity:  potential infinity, actual infinity, and transcendental infinity.  Yikes!  This infinity stuff is difficult!!!



Most people are familiar with the potential infinity, which is
“a non-terminating process (such as "add 1 to the previous number") produces an unending "infinite" sequence of results, but each individual result is finite and is achieved in a finite number of steps”.
 
An example of potential infinity is time. Time began at the Big Bang.  Since then, we’ve added seconds, hours, years, millennia, etc until we reached the present.  When looking toward the future, we will continue to add units of time into the infinite future.  However, at any moment in time you can stop and you have a finite amount of time between t=0 and t=0+x. The potential future time is infinite, but it never becomes an actual infinite or a completed infinity.

An actual infinity is also called a completed infinity.  An example of this is the set of all numbers.  One can continuously count numbers into infinity, which is a potential infinity.  The set of all numbers is an actual infinity.  Another example is length.  A yard has a finite length; however, if you were to start at the beginning of the yard and move only ½ the distance from the start to the end, and then repeat this at ½ the distance between the ½ way point and the end, and then repeat this at the ½ the distance between the ¾ way point and the end, and repeat this again…..you could do this an infinite number of times (it would never end).  The act of repeatedly measuring ½ the distance is a potential infinity.  The yard is a completed infinity because it contains a potential infinity, but a yard is not infinite.  It’s important to note that an actual infinity does not truly exist, but represents an infinite subset.

 
So, back to the infinite regress….an infinite regression is a series of repeating subtractions into negative infinity.  One can count backwards from t=0 to t=0-1=-1 to t=0-1-1=-2 to t=0-1-1-1-…. > -∞, but they will never actually reach negative infinity.  It is a potential infinity because one more unit can always be subtracted from the series.  It can never be completed to be an actual infinity.  The infinity symbol, ∞, represents the concept of not having a limit, but it is not a number anyone can count to.

If the universe has an infinite past, then as we rewind the clock past the Big Bang, time becomes an infinite regression to negative infinity; however, time moves forward.  Negative infinity is not a number and has no limit, so how does one move forward from negative infinity?  There is no point to start from.  Without a starting point, there is always more time to add before the present so one never arrives at the present.  Actually, one never arrives at a -1010,000 years either.  To say otherwise is treating infinity as a finite number and not a limitless concept.  

A proposed solution is to say that one can count from negative infinity if they never started counting but have always been counting from an infinite past.  This is circular reasoning.  The conclusion is presupposed in the premise.  This is essentially saying that an infinite regression is possible if an infinite regression is possible.  This alone makes the solution logically invalid, but let’s explore the possibility anyway.

Let’s say the past is represented by negative numbers, zero is the present, and positive numbers are the future.  Let’s say you never started counting but have been counting from an infinite past.  An infinite amount of time later, you are still counting negative numbers.  An infinite amount of time after that, you are still counting negative numbers.  An infinite amount of time after that?  Still negative numbers.  To say otherwise means you haven’t really been counting from negative infinity, which is an unlimited amount of negative numbers, but have changed infinity into a number.  But there’s a problem with this…..adding infinity to negative infinity is the same as subtracting infinity from itself, which has an undefined solution…but it gets worse for infinity!! 

Hilbert’s Hotel is a thought experiment created by David Hilbert, a mathematician, to show how infinity doesn’t work in the real world.  This hotel is infinitely large and all of the rooms are full.  If an infinite number of people come, it still has room to hold them, since those in room one can move to room two, and those in room two can move to room three, etc.  If an infinite number of aircraft carriers come with an infinite number of buses on them each containing an infinite number of people in them, there would still be enough room even though the hotel is full.  If an infinite number of people leave, an undefined number of rooms remain full.  If everyone in an even-numbered room leaves, of which there would be an infinite number, there would still be an infinite number of odd rooms occupied.  If all but five people leave, which would also be an infinite number, there will only be five rooms filled.  An infinite number of rooms were vacated in three different ways, yet in one scenario there are an undefined number of full rooms, in another there are an infinite number of full rooms, and in another there are only 5 full rooms.  I think it is safe to agree with Hilbert when he said this:

“The infinite is nowhere to be found in reality.   It neither exists in nature, nor provides a legitimate basis for rational thought.  The role that remains for the infinite to play is solely that of an idea.”

The inevitable question then becomes, “What about God?  Isn’t he also infinite?”  That’s where the third type of infinity comes in, the transcendental infinity.  According to the Internet Encyclopedia of Philosophy,

 “a transcendental infinity transcends human limits and detailed knowledge and might be incapable of being described by a precise theory.”

I like to think of it as qualitative infinity instead of quantitative infinity.  God is omnipotent (all-powerful), so he can do anything that can be done.  God is omniscient (all-knowing), so he knows everything that can be known.  God is omnipresent (all-present), so he is everywhere. 

“If you picture time as a straight line along which we have to travel, then you must think of God as the whole page on which the line is drawn.” – C.S. Lewis, Mere Christianity

In summary, an infinite number of anything (things, time, causes, etc) cannot exist in reality.  Infinity is nothing more than an idea, concept, or mathematical tool.  The conclusion can be drawn independent of science that the universe, and/or multi-verse, is finite in both time and material.


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